The present disclosure relates particularly to a semiconductor laser element suitable for use as an edge-emitting semiconductor laser and to a manufacturing method of the same.
The higher the semiconductor laser output becomes, the greater the amount of heat generated at the edges of the resonator, likely resulting in a short service life due to damage to the edges. Damage to the edges takes place in the following mechanism.
That is, when a current is injected, a nonradiative recombination current flows via a surface level existing on the edge. The carrier density is higher near the edges than inside the laser, thus resulting in large photoabsorption. This photoabsorption generates heat, reducing the bandgap energy near the main emission edge and leading to even greater photoabsorption. Such a positive feedback process gives rise to an excessive increase in temperature of the main emission edge having high optical power density.
As a structure adapted to suppress the heating of the edges causing by the above positive feedback, for example, Japanese Patent Laid-Open No. Hei 10-75008 (hereinafter referred to as Patent Document 1) describes the formation of a p-side electrode over the entire surface of the edges to ensure proper heat diffusion from the edges. However, the structure in related art described in Patent Document 1 causes the p-side electrode to be pulled during cleavage, resulting in peeling of the p-side electrode or hanging of the p-side electrode on the edge.
As a structure adapted to prevent peeling and hanging of the p-side electrode, on the other hand, Japanese Patent Laid-Open No. 2002-084036 attempts to solve the problem by moving the p-side electrode back from the edge.